Carbon nanotubes: properties,synthesis, purification,and medical applications

Current discoveries of different forms of carbon nanostructures have motivated research on their applications in various fields. They hold promise for applications in medicine, gene, and drug delivery areas. Many different production methods for carbon nanotubes (CNTs) have been introduced; functionalization, filling, doping, and chemical modification have been achieved, and characterization, separation, and manipulation of individual CNTs are now possible. Parameters such as structure, surface area, surface charge, size distribution, surface chemistry, and agglomeration state as well as purity of the samples have considerable impact on the reactivity of carbon nanotubes. Otherwise, the strength and flexibility of carbon nanotubes make them of potential use in controlling other nanoscale structures, which suggests they will have a significant role in nanotechnology engineering.     

Silicon Affects Rice Growth,Superoxide Dismutase Activity and Concentrations of Chlorophyll and Proline under Different Levels and Sources of Soil Salinity

Silicon - Silicon (Si) application shows beneficial effects on growth and salt tolerance of plants; however, its effects on the rice (Oryza sativa L. var. Hashemi) growth, superoxide dismutase...     

A mathematical model to calculate real cost/performance in software distributed shared memory on computing environments

One of the important factors in high-performance computing (HPC) is the cost/performance ratio. Calculation of cost/performance ratio is the main criterion for the separation of hardware computing systems (supercomputers) from software computing systems (Cluster, Grid, Peer-to-Peer). There are various economic methods to calculate hardware cost. In addition, there are numerous methods in software engineering to calculate the cost of developing and programming the scientific and engineering software. The computing power in the aforementioned systems is basically calculated with programs like LINPACK and HPCL. The inter-process communication is considered as a variable in calculating the cost of executing the scientific programs, whose nature and amount depends on the program execution itself. As there is a high dependency of effective variables in cost calculation of inter-process communications during the program execution, it should be used for calculating the cost of any application. This paper complements the existing methods by presenting a more comprehensive and accurate method to calculate the real cost of distributed shared memory (DSM) mechanisms used by HPC Systems. Therefore, a systematic method has been used to achieve a whole equation for DSM costing, determine the effective factors of the cost, and propose a method based on costing economic methods. Effective parameters are classified into two groups, namely DSM-inhere dependent and application-specific dependent parameters. Each parameter is presented and discussed, and the correlation between them specifies the system’s weight on DSM real cost according to which the cost is modeled and validated analytically.     

Quantum dots: synthesis, bioapplications, and toxicity

ABSTRACT: This review introduces quantum dots (QDs) and explores their properties, synthesis, applications, delivery systems in biology, and their toxicity. QDs are one of the first nanotechnologies to be integrated with the biological sciences and are widely anticipated to eventually find application in a number of commercial consumer and clinical products. They exhibit unique luminescence characteristics and electronic properties such as wide and continuous absorption spectra, narrow emission spectra, and high light stability. The application of QDs, as a new technology for biosystems, has been typically studied on mammalian cells. Due to the small structures of QDs, some physical properties such as optical and electron transport characteristics are quite different from those of the bulk materials.     

Liposome: classification,preparation, and applications

Liposomes, sphere-shaped vesicles consisting of one or more phospholipid bilayers, were first described in the mid-60s. Today, they are a very useful reproduction, reagent, and tool in various scientific disciplines, including mathematics and theoretical physics, biophysics, chemistry, colloid science, biochemistry, and biology. Since then, liposomes have made their way to the market. Among several talented new drug delivery systems, liposomes characterize an advanced technology to deliver active molecules to the site of action, and at present, several formulations are in clinical use. Research on liposome technology has progressed from conventional vesicles to ‘second-generation liposomes’, in which long-circulating liposomes are obtained by modulating the lipid composition, size, and charge of the vesicle. Liposomes with modified surfaces have also been developed using several molecules, such as glycolipids or sialic acid. This paper summarizes exclusively scalable techniques and focuses on strengths, respectively, limitations in respect to industrial applicability and regulatory requirements concerning liposomal drug formulations based on FDA and EMEA documents.     

Use of a "composite" vascular access graft in a young child on hemodialysis

Although arterio-venous fistulae (AVF) are currently considered to be the first choice of permanent vascular access for hemodialysis, there are some patients who are not candidates for fistulae and synthetic grafts provide other options. The Thoratec (Vectra) polyurethane vascular access graft is a new prosthetic graft that may be cannulated within days of insertion due to "self-sealing" properties. However, a tendency for kinking at the suture site due to the strong elasticity of this graft, leading to undesirable complications such as thrombosis, have been reported. We describe a surgical modification of the anastomosis by interposing a segment of expanded polytetrafluoroethylene graft (ePTFE, Venaflo) between the native vessels and the polyurethane graft sections in a pediatric patient. This modification may overcome the kinking complication associated with use of the polyurethane graft and the resulting thrombosis.     

Effect of green GO/Au nanocomposite on in‐vitro amplification of human DNA

Recently nanomaterials have attracted interest for increasing efficiency of polymerase chain reaction (PCR) systems. Here, the authors report on the usefulness of green graphene oxide/gold (GO/Au) nanocomposites for enhancement of PCR reactions. In this study, green GO/Au nanocomposite was prepared with Matricaria chamomilla extract as reducing/capping agent for site‐directed nucleation of Au^o atoms on surface of GO sheets. The as‐prepared green GO/Au nanocomposites were then characterised with UV–VIS spectrophotometer and scanning electron microscopy. Later, the effect of these nanocomposites was studied on end‐point and real‐time PCR employed for amplification of human glyceraldehyde‐3‐phosphate dehydrogenase gene. The results indicated that GO/Au nanocomposite can improve both end‐point and real‐time PCR methods at the optimum concentrations, possibly through interaction between GO/Au nanocomposite and the materials in PCR reaction, and through providing increased thermal convection by the GO surface as well as the Au nanostructures. In conclusion, it can be suggested that green GO/Au nanocomposite is a biocompatible and eco‐friendly candidate as enhancer of in‐vitro molecular amplification strategies.Inspec keywords: graphene, molecular biophysics, nucleation, enzymes, gold, nanofabrication, nanocomposites, scanning electron microscopy, nanoparticles, DNA, nanomedicine, ultraviolet spectra, visible spectra, graphene compoundsOther keywords: green GO/Au nanocomposite, polymerase chain reaction systems, green graphene oxide/gold, PCR reaction, as‐prepared green GO/Au nanocomposites, real‐time PCR methods, Au nanostructures, in‐vitro amplification, human DNA, Matricaria chamomilla extract, site‐directed nucleation, Au, CO, CO‐Au